Printer with rotary roll column selecting means

ABSTRACT

A printer comprising a type wheel having types of or type characters in a plurality of columns arranged on the periphery, means for printing the types on the paper, type selecting means for selecting a given type for each of the columns of said type wheel, column selecting means rotating at a predetermined ratio relative to the shaft of said type wheel, said column selecting means being functionally coupled to said type selecting means, and electromagnetic means each corresponding to two or more columns in a group of said column selecting means and functionally coupled to said type selecting means. The type characters of each column are arranged in different phase for adjacent columns and the column selecting means are adapted to actuate the printing means in the same phase difference of the types.

[ 1 Nov. 19, 1974 101/93 C Elmhurst........................... 101/93 C 3,623,428 11/1971 Imahashi....... 3,673,956 7/1972 Huber et al.. 3,728,688 4/l973 Primary Examiner-Robert E. Pulfrey Assistant ExaminerE. l-l. Eickholt Attorney, Agent, or Firm-Dorfman, Herrell and Skillman [57] ABSTRACT A printer comprising a type wheel having types of or type characters in a plurality of columns arranged on the periphery, means for printing the types on the paper, type selecting means for selecting a given type for each of the columns of said type wheel, column selecting means rotating at a predetermined ratio relative to the shaft of said type wheel, said column selecting means being functionally coupled to said type selecting means, and electromagnetic means each corresponding to two or more columns in a group of said column selecting means and functionally coupled to SELECTING MEANS [75] Inventor: Shohachi Nihira, Tokyo, Japan [73] Assignee: Citizen Watch Company Limited,

Tokyo, Japan [22] Filed: May 2, 1973 211 App]. No.: 356,472

[30] Foreign Application Priority Data May/4,1972 1555C; I .;......l.l..l.lT.f47 44378' [52] U.S. 101/93 C, 178/27 [51] Int. B41j 9/32 [58] Field of Search...................... 101/93 C, 95, 99; 340/1725; 178/27 [5 6] References Cited UNlTED STATES PATENTS United States Patent Ni ira PRINTER WITH ROTARY ROLL COLUMN m mw a f cPf fi u m odM S S Tam o m P 6M 6 mwwm m wm a a e e F h Wmnt g n .m rcil es W hfil a ie r 053 D S n m 6 a m e w S m O m g .l n .m& h .m e C tnhpp ma e 3 l dh emn e mm nmm y 0 mma mm c 00 n mccme CXCCCXXC 3 333 3 3 H33U OWOOONW .0 u

1 l l l 11 8 PRINTER WITH ROTARY ROLL COLUMN SELECTING MEANS This invention relates to printers and, more particularly, to printers having selecting means to select given types (or type characters) from a rotating type wheel.

There has heretofore been known in the art a number printer, which uses electromagnetic hammers each having a head spreading plural columns of a type wheel. Digits or types of each column are disposed in different phase with types of adjacent column in order to print one digit at one printing action and in which the electromagnetic hammers are driven a plurality of times to perform printing of one line.

In the above type of the prior-art printer, types of each column must be angularly spaced by the angle equal to the phase difference between both end columns covered by one hammer in order to print one digit at one action. Accordingly, in the printer of which each hammer covers n columns, diameter of the type wheel is increased n times compared to usual type wheel in which hammers are provided at every column.

Also, time required for printing one line is increased n times as the hammer must act n times for one line. Further, this type of the system can hardly be employed for the simultaneous printing of all digits of one line.

An object of the present invention is to provide a printer which can effectively avoid increase of drum diameter and increase printing speed, consumes low power and can be used for simultaneous printing.

Another object of the present invention is to provide a printer of a novel construction, which permits reduction of power consumption of the printer when it is operated, and particularly reduction of the peak value of the consumed current to thereby improve the effi-- ciency of the employed power source.

Further object of the invention is to provide a small size printer which is operated by a small number of electromagnetic means and a simplified construction.

The construction featured by the invention to achieve the above objects comprises a type, i.e. digits or other type cahracters,'wheel having types being either arranged for all columns on an integral member or independently arranged for individual columns, type selecting means such as hammers or select pawls for selecting a given type for each of the columns of the type wheel, column selecting means such as a reset roll, snatch roll or select roll rotating at a predetermined ratio relative to the rotary shaft of the type wheel and functionally coupled to the type selecting means, electromagnetic means such as electromagnets each corresponding to two or more columns in a group of the column selecting means and functionally coupled to the type selecting means, an electrical control means for comparing a given type with the type position of said type wheel, said electromagnetic means being controlled by said electrical control means said type selecting means being actuated only when both said column selecting means and said electromagnetic means are simultaneously actuated.

Other objects and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a fragmentary perspective view showing one embodiment of the invention;

FIG. 2 is a fragmentary side view of the same;

FIG. 3 is a fragmentary side view showing another embodiment of the invention;

FIG. 4 is a fragmentary side view showing a further embodiment of the invention;

FIG. 5 is a fragmentary perspective view of the same; and

FIG. 6 is a fragmentary perspective view showing a still further embodiment of the invention.

Referring now to the drawings and particularly to FIGS. 1 and 2, reference numeral 1 designates atype wheel comprising a plurality of digit types. The angular distance between adjacent types in each column can be determined to a small angle in which a hammer head 7a will not touch adjacent types. The types are arranged in groups each of which comprises three columns and phase between the adjacent columns is different from each other by one-third of the aforementioned angle. The type wheel 1 is carried by a rotary shaft 2, to one end of which is secured a type wheel gear 3 engaging with an intermediate pinion 4. The intermediate pinion 4 is integral with an intermediate gear 5 engaging with a reset gear 6. The gear ratios involved are set such that the reset gear 6 completes one rotation for each type pitch angle of the type wheel 1. Numeral 7 designates a plurality of hammers pivotally mounted on a hammer shaft 8 for each column. Each hammer has at one end a hammer head 7a adapted to face one type on the type wheel 1, a reset projection 7b and a locking hook 7c formed at the other end, and is biased in counter-clockwise direction by a hammer spring 9. The hammer spring 9 has such dimensions that its coil portion comes to assume non-stretched state just before the associated hammer head striking the type on the type wheel 1 so that no spring force is exerted to the hammer 7 when the head is in contact with the type. In connection with this drawings, there is provided a play between the hammer 7 and the hook portion of the hammer spring 9 so that the flying of the hammer is not impeded until it strikes the type. Numeral 10 designates an armature provided for a group of three adjacent hammers 7 for three adjacent type columns. Each group of three has an armature 10 mounted on an armature shaft 11, and each armature is biased toward the locking hook 70 by an armature spring 13 hooked at one end to magnet support plate 12. Normally, each armature engages with the locking hooks 7c so that the hammer spring 9 is held in tensioned state. Numeral 14 designates a reset gear shaft, which is provided with a select timing disk 15 secured to its one end and a reset roll 16. An end timing disk 17 is secured to the rotary shaft 2 to produce a signal for each rotation thereto, and a timing signal detector 18 is provided to be communicated with the timing disk. The select timing disk 15 is faced by a select timing signal detector 19. The select timing disk 15 is made of a magnetic material and has six peripheral projections 15a, so that the detector 19 detects flux changes as these projections pass it to thereby produce six signals per each rotation of the disk. The reset roll 16 is adapted to abut to the reset projection 7b of each hammer 7 and is so configured at each column that is consists of a maximum diameter as flying arresting portion 16a covering an angle of more than 240, a minimum diameter flying allowing portion 16b, and a reset portion 16c covering an angle less than l20. There is a phase difference of 120 between adjacent columns of the reset roll, so that the phase difference of the reset roll corresponds to the phase difference of the types of type wheel.

Numeral 20 designates electromagnets individually associating with the respective armatures and mounted on the magnet support plate 12. Numeral 21 designates an ink ribbon, numeral 22 a recording sheet, and numeral 23 a sheet feed roller. These parts are mounted in the well known manner. The reset gear 6 is driven from a motor (not shown) and rotated in the counterclockwise direction as indicated by an arrow.

In operation, when the end timing disk 17 and end timing signal detector 18 co-operate to produce end timing signals, the signals are detected by a printer control circuit (not shown) so that the printer and printer control circuit are synchronized as is well known in the art. The select timing disk and select timing signal detector 19 co-operate to produce select timing signals. From each select timing signal the printer control circuit can read which type of which column of the type wheel 1 is coming to the printing position.

Upon appearance of a print signal, the printer control circuit acts to detect whether or not a given type of a given column is coming to the printing position, and upon detection of a proper signal it energizes the corresponding electromagnet 20.

Six signals produced per each rotation of the reset gear 6 are used for printing three types. Two consecutive signals are used to actuate the electromagnet 20, the preceding one serving as energization and the succeeding one serving as de-energization. For checking of selected type in the printer control circuit, the last preceding signal is used.

The energized electromagnet 20 attracts the associated armature 10. When the armature 10 is attracted, it detaches from the locking hooks 7c of the associated three hammers 7. Thereupon, however, the hammers 7 cannot be freed for flying since their reset projection 7b is held by the flying arresting portion 16a of the reset roll 16.

In the course of the rotation of the reset roll a given one of the three hammers 7 falls on the flying allowing portion 16b, whereby the associated hammer flys under the pulling action of the hammer spring 9 and its hammer head 7a striking the given type on the type wheel 1 through the ink ribbon 21 and recording sheet 22, thus imprinting the digit on the recording sheet 22.

When the hammer strikes the type, it is already freed from the action of the hammer spring 9, so that after striking it bounces back and by the hammer spring 9 it is engaged with the reset portion 16c of the continuously rotating reset roll 16. Thus the hammer is held in the initial biased position.

Before the bouncing back of the hammer from the type, the electromagnet 20 has been de-energized, so that when the hammer 7 comes back to its initial position, its locking hook 7c is engaged by the armature 10 by the force of the armature spring 13. At this time, since the other two hammers 7 not released for flying is remained in the position of FIG. 2, the armature 10 engages with all three hammers, so that all parts back to the home position.

When the type of next column arrives to the printing position, the electromagnet 20 is energized again. Thus, the electromagnet acuates three times for printing given types for the three columns during one revolution of the type wheel.

In this way the printing of one line after appearance of a print command is completed in one revolution of the type wheel 1, and subsequently the ink ribbon 21 is fed by a wel-known method and also the recording sheet 22 is fed by the sheet feed roller 23, thereby completing the entire process for one line.

FIG. 3 is a side view showing part of another embodiment of the invention having a construction of a snatch roll type. In FIG. 3, a snatch roll 29 is used in place of the reset roll 16 in the embodiment of FIGS. 1 and 2, and also some associated parts are replaced. In this embodiment, the hammer 7 has neither reset projection 7b nor locking hook 7c, and it is biased not with hammer spring 9 but is biased in the opposite direction with a spring 25. The hammers 7 are held in engagement with a hammer stopper 26 extending parallel to the rotary shaft 2.

Numeral 27 designates a hammer drive member individually associating with the respective hammers 7, and each is biased by a spring 28 in the direction away from the type wheel 1 and snatch roll 29. Also each hammer drive member is held by the hammer stopper 26 and also its vertical movement and retreatment are restricted by a pair of guides 30 with slight allowance for flapping.

The hammer drive member 27 has a driven hook 27a and trigger hook 27b. The trigger hooks 27a of three hammer drive members 27 are engaged by one armature 10.

The snatch roll 29 is mounted on the reset gear shaft 14 and has drive hooks 29a having phase difference of in conformity with the phase difference of the types of the type wheel 1. The electromagnets 20 are similar to the previous embodiment except for their orientation. The type wheel 1, type drum gear 3 and other parts are all the same as in the previous embodiment of FIGS. 1 and 2.

In operation, when a given type comes to the printing position, the corresponding electromagnet 20 is energized to attract the associated armature 10 to the electromagnet 20 similar to the embodiment of FIGS. 1 and 2. Since trigger hooks 27b of three hammer drive member 27 engage with the armature 10, these hammer drive members 27 are downwardly tilted, so that their driven hooks 27a fall within the orbit of the drive hooks 29a of the snatch roll 29. Immediately thereafter, only a given drive hook 29a engages with a driven hook 27a of the corresponding hammer drive member 27, but for other columns of different phases no engagement takes place. Thus, the hammer drive member 27 of the given column strikes the associated hammer 7 and flys in union therewith to print the given type, and then it bounces back.

Before this bouncing, the electromagnet 20 has already been de-energized, and the drive hook 29a of the snatch roll 29 gets off the orbit of the driven hook 27a, so that it has no effect upon .the subsequent returning of the hammer by the spring 25 and returning of the hammer drive member 27 by the spring 28.

In the above way, the printing operation of action similar to the previous embodiment of FIGS. 1 and 2 takes place to complete the entire process.

FIGS. 4 and 5 show a further embodiment of the invention having a construction of the simultaneous line printing type. Numeral 31 designates a rotary shaft,

which is coupled to a select roll 32 through gear means (not shown) to rotate in the same direction. The select roll 32 completes one rotation for the one pitch movement of the type wheel 33. The select roll 32 has projection 32a for individual columns, and adjacent columns are shifted by 120 degrees.

The type wheel 33 comprises independent wheels for individual columns. These wheels have the same hooks 33a and types 33b spaced at same pitch. Also, the wheels are provided with reset ends 33c located at different phase for the individual columns and are frictionally coupled to the rotary shaft 31. Further, select pawls 34 are provided for the individual columns and biased with springs 35 such that they will be engaged with a hook 33a of type wheel 33. Each selectpawl 34 has a hook 34a engaging with the corresponding end 36a of an associated trigger lever 36. The trigger lever has a notch 36 at the other end, with which an armature is engaged. Each trigger lever 36 has a central slot 36c extending in a direction at right angles to its longitudinal direction. A trigger lever guide 37 extending parallel to the rotary shaft 31 engages with slots 36c to prevent the movement of the trigger levers 36 is biased clockwise by a triggerlever spring 38 so that end 36a is engaged with the hook 34a of the associated select pawl 34. Numeral 39 designates a select pawl guide having a reset edge 39a which engages with reset ends 330.

In this embodiment, each electromagnet is also provided for three columns. Three columns in one group are constituted by the three different type wheels. The three type wheels are arranged such that phase difference between types 33b is one-third of the type pitch. This corresponds to the phase difference of the projections 32a of the select roll 32.

The rotary shaft 31 is driven by a drive means (not shown) to make a reciprocal turn within about 180 in one line printing period. Numeral 40 designates a platen which is interlocked to the afore-mentioned drive means to execute one reciprocation against the type wheel 31. Numeral 41 designates a pawl clear bar also interlocked to the afore-mentioned drive means to cause rotation of the select pawls 34.

In operation, when thedrive means is operated in response to a print command the rotary shaft 31 is rotated from the illustrated position in the clockwise direction and the type wheel 33 is rotated in the clockwise direction, and also the select roll 32 is rotated in the same direction.

In course of this rotation, when a given type of a given column comes to the engaging position with respect to the select pawls 34 and the corresponding projection 32a of the select roll 32 comes to face the corresponding trigger lever 35, the printer control circuit as mentioned earlier in the embodiment of FIG. 1 energizes the corresponding electromagnet 20 to attract the associated armature 10. As a result, the three trigger levers 36 engaged by the armature are activated. However,in other columns than the given one the projections 32a of the select roll 32 are not positioned to face the respective trigger levers 36, so that these trigger levers 36 merely swing about their end 36a and do not detach from the associated select pawls 34. On the other hand, the trigger lever 36 for the given column rotates about the projection 32a of the select roll 32, so that its end 36a detaches from the hook 34a of the associated select pawl 34. As a result, the select pawl 34 of the given column is rotated by the associated spring 35 in the counterclockwise direction to be engaged with the hook 33a of the type wheel 33 of the given column. Thus, the type wheel 33 is locked by the pawl and consequently slips on the rotary shaft 31 and thereby holding the given type in the position to face the platen 40. This sequence of actions takes place for each column, so that given types of given columns are all held in position to face the platen 40. In this way, the type select operation is completed. Thereafter, at the end of the forward stroke of the rotary shaft 31 the afore-mentioned urging action of the platen 40 is caused by the drive means to effect printing on the recording sheet 22. I

Subsequent to the printing, the platen 40 is retreated, while at the same time the pawl clear bar 41 is moved toward the select pawls 34 to return the select pawls 34 to the initial position, whereby the trigger levers 30 are engaged by the hooks 34a of the returned select pawls 31 to recover the initial state. Subsequently, the clear bar 41 is returned to the initial position, whereupon the rotary shaft 31 rotates in the opposite direction, that is, in the counterclockwise direction. Following this, the type wheel 33 is rotated in the counterclockwise direction until its reset end 330 abuts to the reset edge 39a of the select pawl guide 39 and is held in the initial position. Concurrently, the ink ribbon 21 and recording sheet 22 are appropriately fed, thus printing operation for one line is completed.

While the preceding embodiment of FIGS. 4 and 5 has had a construction where the type wheel is frictionally coupled, it will be apparent that the invention can also be effectively applied to the well-known simultaneous line printing system having a type wheel rotated by a built-in spiral spring in one direction and also in the well-known simultaneous line printing system where select pawls are coupled to a reciprocating sector gear.

FIG. 6 is a perspective view, partly broken away, showing a still further embodiment of the invention. It has a consctruction similar to that of the embodiment of FIG. 1, but its function is different therefrom as described hereinafter in detail.

To simplify the description, similar or corresponding parts to those in FIG. 1 are designated by same reference numerals. Type wheel 1 is secured to the rotary shaft 2. Types 1a provided over the periphery of the type wheel 1 are arranged in the same phase. Secured to the rotary shaft 2 is a character pulse disk 42 having peripheral lobes individually corresponding to the repective rows of the types 1a. A character pulse detector 43 is disposed to face the character pulse disk 42. The rows of the types 1a of the type wheel 1 and the lobes of the character pulse disk 42 are arranged at a constant interval except for a blank portion subtending an appropriate angle as shown in detail in FIG. 6. A pulley 44 is also secured to the rotary shaft 2, and this pulley 44 is coupled to a pulley 45 secured to the reset gear shaft 14 by an endless belt 46 passes round them. The reset gear shaft 14 is adapted to complete one rotation for every three rotations of the rotary shaft 2. A reset roll 16 similar to that of FIG. 1 is also secured to the reset gear shaft 14. The opposite ends of the reset gear shaft 14, however, are slightly different from the case of the FIG. 1. More particularly, at one end a column pulse disk 47 having three peripheral lobes is secured to face a column pulse signal detector 48, and at the other end an end timing disk 17 having one peripheral lobe is secured. Although not shown in the drawing, an end timing signal detector is disposed to face the end timing disk 17. A reset bar 49 is disposed on the flying side, of the hammer row 7. The reset bar 49 is secured to a lever 50, which is pivotally mounted on a fixed pin (not shown). A cam roller 51 is provided on the lever 50. The cam roller 51 is moved by the cam surface of a reset cam 52 secured to the rotary shaft 2.

The operation of this embodiment will now be described.

Upon the start of the printer, a motor (not shown) is started to rotate the rotary shaft 2 and reset gear shaft 14. When the signal from the end timing disk 17 is coupled to a printer control circuit (not shown), the printer and printer control circuit are synchronized to be ready for the line printing operation. Similar to the embodiment of FIG. 1, the signals from the character pulse disk 42 and column pulse disk 47 are coupled to the printer control circuit so that a given type can be compared with respect to the type and column in the printing position. In this embodiment, it is featured that the rotary shaft 2 is set to execute three rotations for every rotation of the reset gear shaft 14. This means that one rotation of the rotary shaft is assigned to each of three flying allow portions 16b of the reset roll 16.

F IG. 6 shows the state at the start of the printing, with the cam roller 51 engaged in a valley portion of the reset cam 52 and the reset bar 49 separated from the hammer row 7. Immediately after this state, the reset projection 7b of each hammer 7 falls within the flying allow portion 16b of the reset roll 16, and type wheel 1 proceeds from the blank portion to the printing posi tion as it executes one rotation. Then, by a command from the printer control circuit an electric input for a given type is impressed on the corresponding electromagnet 20. Each electromagnet 20 is provided for three hammers 7, but the hammer which is engaged with the flying allow portion 16b can be driven for printing and only given types ce be printed as has been described earlier in connection with the embodiment of FIG. 1.

In the above course of printing, when the blank portion of the type wheel 1 comes to face the hammer row 7, the resetting operation is taken place. When the cam roller 51 is moved by the projection of the reset cam 52, the reset bar 49 causes simultaneous rotation of the hammers 7. Immediately thereafter, the reset projection 7b ofthe hammer 7 is engaged by the flying arresting portion 16a of the roll 16, and also the locking hook of the hammer 7 is engaged by the associated armature 10, thus completing the resetting operation.

Then, the rotary shaft 2 comes to the initial position again. Since at this time the reset gear shaft 14 has been rotated by one-third of one rotation, other flying allow portions 16b of the reset roll 16 arrives to operative position so that printing operation for the column is performed. This operation is repeated three times and the reset gear shaft 14 completes one rotation to complete printing for one line.

In the above embodiment, after a hammer 7 has been actuated for printing, it is free to rotate about the hammer shaft 8, so that there is a tendency that the recording sheet 22 is stained during this time due to the rotation of the type wheel 1. To prevent this it is effective to bias the hammer with a weak spring in the direction opposite to the biasing direction of the hammer spring 9 lest the hammer should touch the recording sheet 22 after it has completed the printing.

While in the foregoing embodiments the electromagnets 20 have been energized only when a print command input is coupled to them, it is of course possible to arrange in such that the electromagnet is normally energized and is de-energized upon reception of a print command signal to release the associated armature. These two alternatives can be suitably selected by preferably setting the power consumption or preferably selecting the circuit design or mechanical means.

As has been described in the foregoing, according to the invention, in the case providing electromagnets each of which is used for n columns, the peak of the power consumption by the overall electromagnets can be reduced to l/n of the conventional value. Also, since the number of electromagnets can be reduced to l/n, the machine can be made in small size. Further, during one electromagnet being continuously operated, the action for one column cannot be impeded even if the type selecting member driven for the previous column is not still be returned, so that the time required for printing one line will not be extended.

Furthermore, since the spacing of adjacent types on the type wheel in the direction of rotation thereof can be made such that types of adjacent columns belonging to the same electromagnet have no effect upon each other, there is no need of increasing the diameter of the type wheel.

What is claimed is:

l. A printer having a printing station comprising a type wheel having type characters arranged about the periphery in a plurality of columns, means including a shaft to rotate said type wheel to advance said columns through said station,

means coupled to said shaft to index a recording sheet through said station once after each passage of said columns through said station,

means for printing the type characters on the recording sheet, type selecting means including electrical control means for selecting a given type character from each of the columns of said type wheel, and

column selecting means rotating at a predetermined ratio relative to the shaft of said type wheel to select one column from a group of adjacent columns, said ratio corresponding to the number of characters in each column, said column selecting means being functionally coupled to said type selecting means and comprising a rotary roll having a number of actuating segments about its periphery corresponding to the number of columns in said group, said column selecting means operable to select a single column from the group in each actuating segment, whereby each column is selected once during each revolution of said roll,

said type selecting means including a common electromagnetic means for said group of adjacent columns, said electromagnetic means being controlled by said electrical control means for comparing a given type character with the type position of said type wheel and being actuated when said given character is in printing position in said station, and said type printing means being actuated only when both said column selecting means and said electromagnetic means are simultaneously actuated,

different phase from the type characters in the other columns in said group, the column selecting means being adapted to actuate the hammer heads of the printing means in the same phase difference as the type characters.

3. A printer in accordance with claim 1 wherein the rotary roll comprises cylindrical members which have one peripheral projection to actuate the printing means in each actuating segment.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,848,527 Dated November 19, 1974 Inventofls) Shohachi Nihira It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the abstract, line I, delete "of";

Column 1, lines 45,46 should read as follows: -achieve the above objects comprises a type Wheel having types, 1. e. digits or other type characters, being ei- Column 2, line 56, "thereto" should be --thereof--;

Column 4, line 6, "wel-known" should be --well-known-;

line 29, "27a" should be --27b--;

Column 7, line 41, "ce" should be --can Signed and sealed this 3rd day of June 1.975.

(SEAL) Attest:

C. MARSHALL DANN RUTH c. MASON Commissioner of Patents Attesting Officer and Trademarks 

1. A printer having a printing station comprising a type wheel having type characters arranged about the periphery in a plurality of columns, means including a shaft to rotate said type wheel to advance said columns through said station, means coupled to said shaft to index a recording sheet through said station once after each passage of said columns through said sTation, means for printing the type characters on the recording sheet, type selecting means including electrical control means for selecting a given type character from each of the columns of said type wheel, and column selecting means rotating at a predetermined ratio relative to the shaft of said type wheel to select one column from a group of adjacent columns, said ratio corresponding to the number of characters in each column, said column selecting means being functionally coupled to said type selecting means and comprising a rotary roll having a number of actuating segments about its periphery corresponding to the number of columns in said group, said column selecting means operable to select a single column from the group in each actuating segment, whereby each column is selected once during each revolution of said roll, said type selecting means including a common electromagnetic means for said group of adjacent columns, said electromagnetic means being controlled by said electrical control means for comparing a given type character with the type position of said type wheel and being actuated when said given character is in printing position in said station, and said type printing means being actuated only when both said column selecting means and said electromagnetic means are simultaneously actuated, whereby when the common electromagnetic means is operated by said control means, the printing means operates to print a character from only one column of said group at any one time, as determined by the segment of said roll which is in actuating position.
 2. A printer in accordance with claim 1 including a hammer for each column, wherein said printing means include a hammer head on each hammer, and wherein the type characters in each column are arranged in a different phase from the type characters in the other columns in said group, the column selecting means being adapted to actuate the hammer heads of the printing means in the same phase difference as the type characters.
 3. A printer in accordance with claim 1 wherein the rotary roll comprises cylindrical members which have one peripheral projection to actuate the printing means in each actuating segment. 